Method of sizing carbonate filled paper



Patented May 5 1931 I UNITED STATES PATENT; orries HAROLD ROBERT RAFTON; OF LAWRENCE, MASSACHUSETTS, ASSIGNOR TO RAFFOLD PROCESS CORPORATION, A CORPORATION OF MASSACHUSETTS METHOD OF SIZING OABBONATE FILLED PAPER No Drawing.

This-invention relates to a method of sizing paper and more particularly to a method of sizing paper filled with carbonate filler.

The principal object of this invention is to 5 provide a method of sizing paper filled with carbonate filler wherein a paraffin emulsion made with a substantially water insoluble type emulsifying agent is added to a paper mix in the beatertogether with a fibre assoau ciating agent, and a restoring agent is added 1 to the resulting mix at the wet end of the paper machine.

Other objects and advantages of this invention will become apparent during the 15 course of the following description.

My invention is directed to sized paper {such 'as' is used for printing purposes for coating raw stock, or the like. It is not directed to waterproof products such as prepared roofing or the like, nor to parafiined papers which normall have a paraflin finish, which makes them su tantially waterproof and usually translucent or transparent and unsuited for the uses to which I wish to put my sized paper.

I have discovered that certain grades of aper filled with carbonate filler may be sized y adding to the paper mix in the beater a paraifin emulsion made with a substantially 'T 39 water insoluble type emulsifying] agent and a,

fibre associating agent prefera ly comprising sodium resinate and alum, and restoring the fibre associating properties of the fibre associating agent which are deteriorated, sometimes even to the point of destruction, by the carbonate filler, by adding a suitable restoring agent such as alum to the resulting mix at the wet end of the paper ma chine.

In the preferred practice of my process I add to fibrous material containing a'carbonate filler in a beater or the like a suitable amount of a paraffin emulsion of the above referred to character. In preparing such 45 an emulsion I may use a substantially water insoluble type emulsifying agent such as clay I or even carbonate filler itself. The method of making such emulsions is well known and this method ordinarily comprises heating 50 parafiin above its melting point and adding Application filed September 5, 1928." Serial No. 364,176.

theheated parafiin with vigorous agitation to a suspension of the substantially water.

insoluble material in Water which is preferably maintained at ap roximately the same temperature as that oi the melted parafiin. Vigorous agitation is meanwhile carried on and is contlnued while the emulsion is cooling. I then add to a fibrous mix in a beater, mixer or similar device, the parafiin emulsion and a suitable fibre associating agent to associate the paraffin emulsion with the fibre, said agent comprisin preferably sodium resinate and alum. Pre erabl after the sodium resinate and alum are t oroughly mixed with the fibre I then add carbonate filler, and/or if desired, fibrous materials coming under the definition of carbonate filler hereinafter set forth. It is possible to add all the fibrous constituents and/ or the carbonate filler itself in the beater prior to the addition of the alum or the sodium resinate and alum, but my ex periments have indicated that better results are obtainable when the sodium resinate and alum are added to the fibre in the absence of any carbonate filler,

Moreover in furnishing the beater, I preferably use fresh water or white water which has been clarified so that the sodium resinate alum reaction may completely take place before the addition of carbonate filler in any form to the mix. 7

The amount of sodium resinate I may use is that amount which by itself when precipi tated with alum, and restored with a subsequent quantity of alum, in accordance with my copending application Serial No. 304,168 filed Sept. 5, 1928, would not be sufiicient to size the paper, but would produce a substanuse a greater quantity ofsodiu'mresinate, but 'itis tob'e pointed out that it is possible to secure sizing by my process where there is not enough sodium resinate used to impart sizing.

of itself."

I have found that the fibre associating properties of the sodiumresinate and alum 7e somewhat deteriorated, sometimes even to 1e point of destruction, by the resence of ie carbonate filler before the mix is passed a to the web-forming device of a paper maiine. However I have discovered that the bre associating properties of these materials my be restored by adding a suitable restorig agent such as alum preferably in solution, referably continuously, to the mix at the wet 1d of the paper machine. 1oring the desired properties of the fibre as- )ciating agent and reassociates the emulsion 'ith the fibre with the result that the finished aper produced from such a mix is suitably zed. If the sizing restoring agent were not nployed only such parts of the parafi in emul- .on as would be mechanically filtered out by ,ie fibre would be retained thereon and the aper produced would not be satisfactorily .zed, except possibly at the expense of a reatly increased quantity of parafiin, which 'ould be undesirable because of certain mehanical instability as indicated below, as 'ell as because of prohibitive cost.

It is necessary as indicated to add the re- ;oring agent at or subsequent to the point of ilution of the mix, as I have found that if it e added when the mix is in relatively concenrated condition, and particularly when the elatively concentrated mix is subjected to gitation as is normal in stock chests, the retoring effect is very quickly deteriorated ven to the point of complete destruction. .he restoring effect even when the mix is in he diluted condition is gradually deteriorted, but is substantially unafiected within be time limits that the mix is maintained in he dilute state in the usual paper-making rocedure. Moreover, although agitation in he dilute state hastens to a certain extent the eterioration of the restoring ell'ect, the speed f deterioration is not nearly so pronounced s in the concentrated condition, and from a ractical standpoint I have found that the gitation to which the diluted mix is subected prior to delivery onto the web-forming evice does not deteriorate the restoring efect to a substantial degree. he restoring agent is added at a point in the rocess where there is a minimum of time and itimacy of contact of the constituents of the Although clay is my preferred substantial- 5; water insoluble emulsifying agent I may se also other substantially water insoluble mulsifying agents which do not exist as such riginally, such for example as any agentormed from two mutually precipitating maerials whichis adaptedtoyieldasubstantially rater insoluble coating around the individual articles of parafiin. The method of making uch emulsions is well known. Such an emulion may be completely made prior to addiion to the fibrous pulp, or it may be formed a the pulp by dispersing the paraflin origi- This results in re In other words,-

nally in a soluble material which will prevent its agglomeration in the pulp mass, and then subsequently forming a substantially water insoluble coating on the dispersed parafiin particles by adding to the pulp mass and dispersed paraflin a material which will mutually precipitate the original dispersing material into a substantially water insoluble layer or film around the dispersed parafiin particles.

Papers made in accordance with my invention are sized but because of the relatively large size of the particles in comparison with the nonbreakable paraflin emulsion described in my copending applications Serial No. 304,170 filed Sept. 5, 1928, and Serial No. 304,173 filed Sept. 5, 1928, the sizing is not quite so well distributed throughout the paper. Thus it is usually desirable to use somewhat more paraflin than in the above referred to copending applications. Moreover in order to secure uniform distribution of sizing this invention may advantageously be employed in connection with the process outlined in my copending application Serial No. 230L168 of Sept. 5, 1928. However in view of the fact that the emulsifying agent employed in the practice of this invention is relatively inexpensive, an appreciable net economy results from this process. Moreover, this invention is of great advantage for preparing certain grades of paper where the requirements are not so exacting.

The emulsion herein en'iployed, although reasonably resistant to chemical agencies, especially if the substantially water insoluble emulsifying agent employed be also substantially acid insoluble, has certain defects from a mechanical standpoint which should be taken into account in its use. ficulty is that this emulsion has a tendency to be mechanically unstable, and when subyected to pressure as by the action of the eater, some of the articles mayhave their protective coating oi be released from emulsified condition with consequent release of particles offree paraffin in the stock, which have a tendency to ag glomerate and cause trouble in the paper making process. able to heat the fibre prior to the addition of the emulsion and then raise the beater roll just prior to adding the emulsion, using the roll merely for mixing rather than for beat- K ing purposes thereafter in order to prevent 1 the breakdown of the emulsion by the beater. The action of the fibre associating agent does not seem to have a noticeable breakin U efi'ect on the emulsion itself, and thus the parallin is not thereby directly released from emulsion, but the same defect regarding the action of mechanical agencies on the emulsion as set forth above seems to be inherent in the emulsion whether alone, or when associated with the fibreassociating agent.

The chief difclay removed, and thus For this reason it is desir- L An illustrative furnish which may advantageously be used in practicing my invention is as follows:

Materials added in the beater Pounds Fibrous furnish (e. g. sulphite and soda ulps; 1700 Rosin (added in the form of sodium res nate 10 Parnlfin (added in the form of a substantially water insoluble emulsifier type of emulsion) Alum (ordinary A1g(S04)3-18Hg0) Caflfiiun; carbonate magnesium hydroxide (carbonate Materials added in the beater Pounds Fibrous furnish (e. g. approximately equal parts of sulphlte, soda and old paper stocks) 1800 Rosin (added in the form of sodium resinate) 10 Paraflln (added in the form of a substantially water insoluble emulsifier type of emulsion) 35 Alum \ordinary Al (SO .18H 0) 80 Calcium carbonate magnesium hydroxide (carbonate filler) 200 Material added proportionately and continuously on dilution Pounds Restoring agent, e. g. alum (ordinary A12(SO4,)3.18H30)- 50 In the above formula, the weights of carbonate filler refer to bone dry basis, the weights of all other ingredients being given on the air dry basis.

In regard-to the parafin used, itis to be understood that either low or high melting point'material can be employed. The socalled fully refined paraflin is entirely satisfactorysince it does not import objectionable color to white sheets. However, for purposes of economy, it is often desirable to use 2. less pure material such for example as the material which is commonly known to the trade as semi-refined parafiin scale, containing approximately 1-2 per cent. of oil'and water as impurities, which material Elves satisfactory results. Such msterial-wi perhaps in certain cases have varying melting points but one particular sample used, for example, had a melting oint of approximately 115 F. (46 C.). ther even more impure parallins may be used, especially if the color (whiteness) requirements of the finished aper are not too exacting, or if papers, ot er than white, are to be made.

In place of alum in the practice of my process, both as originally added in the heater,

and as a restormg agent, I may employ with a. measure of success an acid such as sulfuric acid (H,so. an acid salt such as sodium bisulfete (NaHSOl), or a salt of a. trivalent metal, such as ferric iron or the other salts of aluminum. Of the aluminum sslts available I may use the chloride or the like, but I prefer to use ordinary alum.

In place of sodium resinate I may use sstis= factorily in the practice of my process other soaps, such as the olestes, or any partially or completely saponified material, such as Ba.- ponified beeswax.

By the term carbonate filler as employed herein, is intended to be included calcium carbonate, of which lime mud from the causticizing process is one form; calcium carbonate magnesium basic carbonate employed in the paper disclosed in my U: S. Patent No. 1,595,416; calcium carbonate magnesium hydroxide disclosed in my U. S. Patent No.

1,415,391; or other substantially water insoluble normal or basic carbonates of alkaline earth metals, (which expression is herein intended to include magnesium) or compounds, double salts, or physically associated mixtures of these with one or more other acid soluble materials of a substantially water insoluble nature. The term carbonate filler is also intended to include fibrous material and/or other material such as paper coating constituents or the like containing one or more compounds of the character referred to, such as old papers or similar papers, broke, or the like.

By the term wet end of the paper machine is intended to be included those instrumentalities employed in paper manufacture by which and/or in which a relatively concentrated paper mix is diluted, and treated, conveyed. or fed up to the point or" Web-formation, such as the mixing box, regulating and proportioning devices, rifilers, troughs, screens, head boxes, inlets, and the like, including also instrumentslities used in the white water cycle.

When I employ the term parsflin herein, I mean paraflin Wax, which is solid at ordinary or room temperature. I do not mean to restrict myself only to the paraflin hydrocarbons, but mean to include in this term all the hydrocarbons of a. waxy nature substantially unsaponifiable and inert to acidic and alkaline materials under ordinary conditions of temperature and pressure, whether derived from petroleum, shale, lignite, earth wax, or other natural or artificial sources. I do not, however, mean to include in this term material of a pitchy nature, such as bitumen or asphalt.

Where I use the term sodium resinate it is to be understood that I mean it to include any material produced by the action of alkali, generally in aqueous solution, on rosin, or on natural or synthetic resin acid or acids, regsrdless of the exact composition of the product, or the varying composition which different semples may possess.

WhenI use the word paper herein, I use it in the broad sense to include products of manufacture of all types and of all weights and thicknesses, which contain as an essential constituent a consulerable amount of prepared fibre and which are capsble of being produced on a Fourdrinier, cylinder, or other rming, felting, shaping or molding maune.

whil'efiii have described in detail the pre- :rr'ed embodiment of my invention, it is to a understood that the details of procedure, ie proportions of ingredients, and the ar- Lngement of steps may be widely varied ithout departing from the spirit of the m- :ntion or the scope of the subjoined claims.

I claim 1. The method of sizing paper filled with .rbonate filler comprising mixing with fi- 'ous material a par-afl'in emulsion made with substantially water soluble type emulsifyg agent, fibre associating agent, and carbone filler, and thereafter adding a restoring gent under conditions favoring the miniizing of the time of contact of the conituents of the mix, and thereafter making Lper therefrom. 2. The method of sizing paper filled with ,rbonate filler comprising mixing with fi- -ous material a paraffin emulsion made with substantially water,insoluble type emulsiing agent, fibre associating agent, and carmate filler, and thereafter adding a restorg agent under conditions favoring the miniizing of the intimacy and time of contact the constituents of the mix, and thereafter aking paper therefrom.

3. The method of sizing paper filled with rbonate filler comprising mixing with fi- 'ous material a parafiin emulsion made with substantially water insoluble type emulsiing e ent, fibre associating agent, and car mate i'ller, and thereafter adding a fibre ascia-ting restoring agent under conditions voring the minimizing of the intimacy and ne of contact of the constituents of the mix, (1 thereafter making paper therefrom.

4. The method of sizing paper filled with rbonate filler comprising mixing with fious material a paraffin emulsion made with substantial] water insoluble type emulsiing agent, fibre associating agent, and carnate filler, and thereafter adding a sizing storing agent under conditions favoring the inimizing of the intimacy and time of conct of the constituents of the mix, and thereter making paper therefrom.

5. The method of sizing paper filled with rbonate filler comprising mixing with fious material a paraflin emulsion made with substantiall water insoluble type emulsiing agent, bre associating agent, and carnate filler, and thereafter adding a restoragent the wet end of the paper mame.-

8. The method of sizing paper filled with rbonate filler comprising mixing with fious material a parafiin emulsion made with substantially water insoluble type emulsiing agent, carbonate filler, and fibre assottingagent comprising saponified material d precipitant therefor, and thereafter adding to the resulting mix a restoring agent for said fibre associating agent at the wet end of the paper machine.

7. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraflin emulsion made with a substantially water insoluble type emulsifying agent, carbonate filler, and fibre associating agent comprising saponified material and a salt of a trivalent metal, and thereafter adding to the resulting mix a restoring agent for said fibre associating agent at the wet end of the paper machine.

8. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraffin emulsion made with a substantially Water insoluble type emulsi- I fying agent, carbonate filler, and fibre associating agent comprising saponified material and a salt of aluminum, and thereafter adding to the resulting mix a restoring agent for said fibre associating e ent at the wet end of the paper machine.

9. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraffin emulsion made with a substantially water insoluble type emulsi-- fying agent, carbonate filler, and fibre associating agent comprising sa onified material and alum, and thereafter ad ing to the resulting mix a restoring agent for said fibre assov ciating agent at the wet end of the paper machine.

10. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraffin emulsion made with a substantially Water insoluble type emulsifying agent, carbonate filler, and fibre associating agent comprising sodium resinate and alum, and thereafter adding to the resulting mix a restoring agent for said fibre associating agent at the Wet end of the paper ma chine.

11. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraffin emulsion made with a substantially water insoluble type emulsifying agent, carbonate filler, and fibre associating agent comprising a saponified material and precipitant therefor, and thereafter adding to the resulting mix a salt of a trivalent metal at the wet end of the paper machine.

12. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a parafiin emulsion made with a substantially water insoluble type emulsifying agent, carbonate filler, and fibre associating agent comprising saponified material and precipitant therefor, and thereafter adding to the resulting mix a salt of aluminum at the wet end of the paper machine.

13. The method of sizing paper filled with Tito fibrous material a parafiin emulsion made witha substantially water insoluble type emulsifying agent, carbonate filler, and fibre associating agent comprising saponified material and precipitant therefor, and there-; 1 after adding to the resulting mix alum at the wet end of the paper machine.

14:. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraffin emulsion made with a substantially water insoluble type emulsifying agent, carbonate filler, sodium resinate, and alum, and thereafter adding to the resulting mix alum at the wet end of the paper machine.

15. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraflin emulsion made with a substantially water insoluble type V emulsifying agent, carbonate filler, and fibre associating agent comprising saponified material and precipitant therefor in an amount insufficient of itself to im art'substantial' sizing to the-paper, aud t ereafter adding to the resulting mix a restoring agent for said fibre associating agent at the wet end of the paper machine.

16. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material a paraifin emulsion made with a substantially water insoluble type emulsifying agent, carbonate filler, sodium resinate in an amount insufiicient of itself to impart substantial sizing to the paper, and

alum, and thereafter adding to the resulting mix aiam at the wet end of the paper machine.

17. In a method of the character described, the step of adding a restoring agent at the Wet end of the paper machine.

18. In a method of the character described, the step of adding a salt of a trivalent metal at the wet end of the paper machine.

19. In a method of the character described,

the step of adding alum at the wet end of-the paper machine.

In testimon whereof I aifix my signature.

HAR LD ROBERT RAFTON.

CERTIFICATE or CORRECTION.

itent No. 1,803, 651. V Granted May 5, 1931; to

HAROLD ROBERT RAFTON.

It is hereby certified that error appears in the printedspeciiication of the tbove numbered patent requiring correction as follows: Page 4, line 14, claim for the word "soluble" read insoluble; and that the said Letters Patent should re read with this correction therein that the same may conform to the record of :he case in the Patent Office.

Signed and sealed this 4th day of August, A. D. 1931.

Wm. A. Kinnan, Seal) Acting Commissioner of Patents. 

